I'm pretty sure that excess fat gets stored as fat directly, or incorporated into cell walls during reconstruction. Excess fat may not be as harmful as excess protein and carbs as it causes some other mechanisms to come into play, but that's just my bro-science.

I think the best thing a person can do is to eat and live in a way that promotes insulin sensitivity, then all the other endocronological magic happens all by itself.

I think you're absolutely right. That's a very believable explanation in my opinion.

I was doing some more research on Taubes and trying to understand exactly what his view is on fat (since he usually only talks about the endocrinological reaction that's induced by carbs). I found a really interesting discussion of the topic from 9:38 to 16:00 of the following video: http://www.youtube.com/watch?v=DfXzRbzUpoQ#t=9m38s

He argues that it's very difficult to gain weight by eating fat because it's hard to consume large enough quantities. Apparently, there was an old study with inmates where they tried to make them gain 20% body weight by feeding them additional fats (on top of their ordinary diets). I guess they couldn't do it because at some point the inmates would refuse to eat any more fat during the meal. They were simply too stuffed to eat another pork chop or steak. Then the researchers tried getting them to eat additional carbs and were eventually able to get them up to 10,000 calories per day. (I think the subjects originally started at around 3,000 calories per day.) With fat, the best they were able to do was get the inmates to eat an additional 800 calories per day in the form of butter.

So I guess the argument is that fat is much more satiating. But with excessive carb consumption you often feel unsatisfied a few hours later and want to eat a bunch of carbs again. (I'm not sure whether that's caused by insulin spikes themselves or just insulin resistance in general.) I've definitely noticed something along these lines with myself. A few years ago, I would sometimes eat a bunch of pasta or fried rice before bed. And I'd wake up extremely hungry. In fact, I'd be so hungry that my stomach would actually hurt and be growling. If I eat a large quantity of bacon before bed, I wake up feeling fine.

It really is all about balance and ratios. What primal and paleo people talk about is not a zero carb diet. The only way to effectively do that is to eat only meat. Atkins for example banned foods with both a high glycemic index (wheat, bread, pasta) and a low glycemic index (black rice, fruits, vegetables). Banning low glycemic index foods was the inherent problem. In primal eating, you'll consume a lot of meat (i.e. protein), but you also consume complex soluble fiber, carbohydrates, etc in veges and fruit. The idea is to avoid the superconcentrated refined sugars and carbs that are in breads, pasta, pastries, etc.

Essentially, foods with high glycemic indexes that are readily accessible (which does not include fruit and vegetables) to the GI tract like breads and pastas cause insulin spikes. These insulin spikes above and beyond the norm causes your muscles to take in the glucose. In addition, it promotes glucose being converted into fat as was said. Constant high levels of insulin caused by standard american diets cause a lot of cells that have insulin receptors to down regulate them...in essence you get insulin resistance.

Your body is perfectly capable of interchanging fat and glucose and does so pretty readily. It can interconvert between the two if needed to store glycogen in the liver (fat to sugar via metabolism and gluconeogenesis) or sugar to glycogen.

I'd stay away from this folly of an idea of low-carb or zero carb. We live in a world where a lot of our food is has insane levels of high glycemic carbohydrates. Any diet that cuts out a lot of refined sugars for example would suddenly be "low carb." It's just low carb relative to what we typically eat.

Dear OP: To answer your question, it is this: "Fats have no relationship to insulin levels."

There, wasn't that simple?

Haha, yep. Thanks.

Here are a couple of related quotes:

Originally Posted by Margaret Floyd

Here’s something really important to know about fat: it does not trigger the hormonal dance that creates fat storage the way that sugar and other starchy carbohydrates do.

When you eat something sweet, your blood sugar levels increase too quickly, and your pancreas secretes the hormone insulin to take the excess sugar out of your blood. Insulin is a fat storage hormone. It stores that extra sugar first as glycogen, and then as triglycerides (fat) once glycogen stores are full.

Originally Posted by Mark Sisson

Eventually, the insulin helps the glucose finds it way into your fat cells, where it is stored as fat. Again – because it bears repeating – it’s not fat that gets stored in your fat cells – it’s sugar.

If fat is not getting stored in the fat cells, then where is it going? Is it just flowing through the bloodstream until it is used for energy? Or are the muscle and liver cells just able to store more fat as energy (therefore relieving the need to store the fat in the fat cells)? Or can excess fat be converted into triglycerides and then stored in fat cells?

If fat is not getting stored in the fat cells, then where is it going? Is it just flowing through the bloodstream until it is used for energy? Or are the muscle and liver cells just able to store more fat as energy (therefore relieving the need to store the fat in the fat cells)? Or can excess fat be converted into triglycerides and then stored in fat cells?

Here is a very clear explanation that may answer your question Though it's a little detailed, it lays out the storage cycle of fat and explains the role insulin plays in directing how fat storage or usage occurs.